Method for adjusting an amount of discharge between a plurality of liquid discharge nozzle units, an ink jet driving method using such method of adjustment, and an ink jet apparatus

Abstract

A method for adjusting an amount of discharge is to adjust the amount of liquid between liquid discharge units to discharge the liquid by driving a plurality of electrothermal transducing elements, which uses a plurality of liquid discharge units arranged corresponding to each liquid path for the creation of air bubbles for discharging the liquid, at the same time, being arranged to be capable of being driven individually. This method comprises the step of variably controlling the starting time of driving signal applied to each of the electrothermal transducing elements for the creation of air bubbles in each of the discharge units. The variable control thereof makes it possible to suppress the variation of discharge amount of liquid between the liquid discharge units, hence maintaining the amount of liquid discharged from each of the discharging units at a constant level to obtain printed images of higher quality.

What is claimed is:  
     
       1. An ink jet apparatus provided with an ink jet head provided with plural nozzles at least two of which each have a plurality of electrothermal transducing elements arranged to create air bubbles for discharging ink and to be driven individually, the ink jet apparatus comprising: 
       temperature detection means for detecting temperatures of the ink jet head;  
       data storing means for storing correction data to correct a variation of discharge amount between discharge nozzles or between discharge nozzle groups;  
       driving means for applying driving signals, each including a main pulse to enable the electrothermal transducing elements to generate thermal energy for the creation of bubbles, a pre-pulse preceding the main pulse for heating in a manner not intensive enough to create any bubbles, and a quiescent time between the main pulse and the pre-pulse, in accordance with recording data; and  
       controlling means for performing a first control to change the conditions of the pre-pulse in accordance with data stored in said data storing means, and also performing a second control to shift an application timing of main pulses between electrothermal transducing elements in each of one or more nozzles,  
       wherein the first control is performed in accordance with the result of the detection by said temperature detection means to suppress a variation of discharge amount caused by changes in the temperature of ink, and the second control is performed in accordance with the data stored in said data storing means to suppress the variation of discharge amount caused by individual difference between discharge nozzles or discharge nozzle groups.  
     
     
       2. An ink jet apparatus provided with an ink jet head provided with plural nozzles at least two of which each have a plurality of electrothermal transducing elements arranged to create air bubbles for discharging ink and to be driven individually, the ink jet apparatus comprising: 
       temperature detection means for detecting temperatures of the ink jet head;  
       data storing means for storing correction data to correct a variation of discharge amount between discharge nozzles or between discharge nozzle groups;  
       driving means for applying driving signals, each including a main pulse to enable the electrothermal transducing elements to generate thermal energy for the creation of bubbles, a pre-pulse preceding the main pulse for heating in a manner not intensive enough to create any bubbles, and a quiescent time between the main pulse and the pre-pulse, in accordance with recording data; and  
       controlling means for performing a first control to change the conditions of the pre-pulse in accordance with data stored in said data storing means, and also performing a second control to shift an application timing of main pulses between electrothermal transducing elements in each of one or more nozzles,  
       wherein the second control is performed in accordance with the result of the detection by said temperature detection means to suppress a variation of discharge amount caused by changes in the temperature of ink, and the first control is performed in accordance with the data stored in said data storing means to suppress the variation of discharge amount caused by individual difference between discharge nozzles or discharge nozzle groups.  
     
     
       3. An ink jet apparatus according to  claim 1  or  claim 2 , wherein heating means is provided to heat the ink jet head, and when the detected temperature by said temperature detection means is lower than a specific target temperature, a temperature adjustment is performed by said heating means to raise a temperature of the ink jet head to reach the target temperature. 
     
     
       4. A method for driving an ink jet head provided with a plurality of discharge nozzles and a plurality of electrothermal transducing elements for bubble creation, each electrothermal transducing member being arranged corresponding to each of the plurality of discharge nozzles, by applying a main pulse for applying a bubble creation energy and by applying a pre-pulse preceding the main pulse for heating in a manner not intensive enough to create any bubbles so that an ink liquid droplet is discharged from the discharge nozzles by the bubble creation, the method comprising the steps of: 
       executing a first control by changing an application condition of the pre-pulse in accordance with a detected temperature of the ink jet head together with executing a second control for suppressing a variation of discharge amount due to an individual difference among the discharge nozzles or discharge nozzle groups by adjusting a time difference of an application start of the main pulse for bubble creation among the plurality of electrothermal transducing elements in the discharge nozzles; and  
       suppressing a variation of discharge amount due to a temperature change of the ink by combining the first control with the second control in a case where the detected temperature of ink jet head exceeds a controllable limit temperature of the first control.  
     
     
       5. A method for driving an ink jet head provided with a plurality of discharge nozzles and a plurality of electrothermal transducing elements for bubble creation, each electrothermal transducing member being arranged corresponding to each of the plurality of discharge nozzles, by applying a main pulse for applying a bubble creation energy and by applying a pre-pulse preceding the main pulse for heating in a manner not intensive enough to create any bubbles so that an ink liquid droplet is discharged from the discharge nozzles by the bubble creation, the method comprising the steps of: 
       executing a first control by changing an application condition of the pre-pulse in accordance with a detected temperature of the ink jet head together with executing a second control for suppressing a variation of discharge amount due to an individual difference among the discharge nozzles or discharge nozzle groups by adjusting a time difference of an application start of the main pulse for bubble creation among the plurality of electrothermal transducing elements in the discharge nozzles; and  
       suppressing a variation of discharge amount due to a temperature change of the ink by combining the first control with the second control in a case where the detected temperature of the ink jet head exceeds a controllable limit temperature of the second control.  
     
     
       6. A method according to  claim 4  or  claim 5 , wherein two electrothermal transducing elements are provided per each discharge nozzle, and are arranged in a direction intersecting an ink flow direction toward the discharge nozzle, and the application timing of the main pulses to each of the two electrothermal transducing elements is shifted. 
     
     
       7. A method according to  claim 4  or  claim 5 , wherein two electrothermal transducing elements are provided per each discharge nozzle, and arranged within each discharge nozzle in the direction intersecting an ink flow direction toward the discharge nozzle, and are arranged within each discharge nozzle shifted relatively within the length of the electrothermal transducing element in the direction of ink flow, and the application timing of the main pulses to each of the two electrothermal transducing elements is caused to shift. 
     
     
       8. A method according to  claim 4  or  claim 5 , wherein the ink jet head is an elongated head structured by chip elements, each having a plurality of discharge nozzles, and the chip elements are arranged in one line in an arrangement direction of discharge ports of the discharge nozzles. 
     
     
       9. A method according to  claim 4  or  claim 5 , wherein the ink jet head is a head structured by use of a plurality of chip elements, each having a plurality of discharge nozzles, for use of different colors or kinds of ink. 
     
     
       10. A method according to  claim 4  or  claim 5 , wherein the ink jet head is a high resolution head structured by a plurality of chip elements, each having a plurality of discharge nozzles at equal intervals, and the chip elements are stacked while being displaced by pitches corresponding to a recording resolution. 
     
     
       11. A method according to  claim 4  or  claim 5 , wherein the variation of a discharge amount caused by the individual difference between discharge nozzles or discharge nozzle groups is detected by reading out a density unevenness of prints, and the control of discharge amount is performed to eliminate the density unevenness.